1. Field of the Invention
The present invention relates generally to a bearded needle used mainly for Sagara embroidery (looped stitches), and more particularly, to a bearded needle that can attain uniform finishing with stable off-hooking of a thread in Sagara embroidery.
2. Description of the Related Art
As conventional bearded needles, there have been those for a book binding stitcher, a knitting machine, etc. FIGS. 3A and 3B illustrate a bearded needle for a book binding stitcher that has the following configuration. A needle body 1 includes a conical tip 2 formed at a head portion thereof and a tonguelet 4 extending from the conical tip 2 and being bent in a U-shape at a narrow portion 3, wherein a needle eye 5 is formed between the needle body 1 and the tonguelet 4 to form a hooking portion to hook a thread. The width of the needle eye 5 is nearly the same as the width of a thread, but the width of the needle eye 5 is made slightly wider to ensure the smooth sliding of a thread. A thread hooked at the hooking portion is retained to form a U-shape loop, and the width of the U-shape loop can be made narrower by the provision of the narrow portion 3. While friction that is generated when a thread is pulled out is large and the thread could be cut in a case that the width of the U-shape loop is wide, the friction can be reduced by narrowing the width of the U-shape loop (see e.g., Japanese Patent Laid-Open Application No. 63-162290).
A conventional bearded needle used in Sagara embroidery is explained referring to FIGS. 4A to 4C. A bearded needle of this type has the following configuration. A needle body 6 includes a needle shank 6a and a hooking portion 7 formed at a tip portion thereof. The hooking portion 7 includes a narrow shank portion 6b formed at the distal end of the needle shank 6a and a conical projection portion 8 provided at a tip of the narrow shank portion 6b. The conical projection portion 8 has a hooking tip portion 9 that points backward to form a needle eye 6c where a thread is hooked. At the hooking tip portion 9, as illustrated in FIG. 4C, thread guiding grooves 6d where a thread S is hanged on are formed on the two sides of the hooking portion 7. Reference character 6b′ denotes the side of the narrow shank portion 6b, and reference character 9′ denotes the side of the hooking tip portion 9. In order to prevent the hooking tip portion 9 of the bearded needle 6 from trapping by hooking a base cloth when the bearded needle 6 is drawn from the base cloth, the width D from the outer end of the needle shank 6a to the end, on the side of the needle eye 6c, of the hooking tip portion 9 needs to be formed wide enough. There are problems that in the case that the width D is narrow, while it is allowed to form the width of the needle eye 6c wide, the hooking tip portion 9 may hook the base cloth and hence roughening of the base cloth may be caused, and that in the case that the width D is wide, the needle eye 6c and the thread guiding grooves 6d become narrow accordingly, and hence off-hooking of a thread becomes instable.
In Sagara embroidery (looped stitches), there are chain stitch and loop stitch. As illustrated in a step sequence (1) to (10) in FIG. 6, the chain stitch has planar stitches formed by loops connected like a chain. In step (1), a thread S is hooked by the hooking portion 7 of the bearded needle 6 and drawn out from a base cloth C, and the bearded needle 6 is elevated to a top dead center. In steps from (2) to (5), after stopping the rotation of a looper T, the bearded needle 6 is lowered to pierce through the base cloth C, and is inserted into a needle insertion hole Ta of the looper T while the looper T is being rotated clockwise, and the thread S is off-hooked from the hooking portion 7 during the lowering process, and the bearded needle 6 is further lowered. In steps from (6) to (10), the thread S is wound around the bearded needle 6 by the clockwise rotation of the looper T, then the thread S is hooked by the hooking portion 7 of the bearded needle 6 by elevating the bearded needle 6, a new loop P is formed by further elevating the bearded needle 6 inside a previously formed loop P to the top dead center, and the thread S hooked by the bearded needle 6 goes through the previously formed loop P by rotating the looper T counterclockwise to an initial position and moving the base cloth C in the direction indicated by an arrow Y, thereby forming the new loop, resulting in chained loops being formed by repeating the same steps.
Loop stitch, which forms steric stitches (towel face stitches) by forming separate standing-up loops one by one, is explained in a step sequence from (1) to (10) in FIG. 7. Step (1) shows a state that a bearded needle 6 has reached a top dead center, a loop P has been formed on a base cloth C, and the base cloth C has been moved. In steps from (2) to (5), the bearded needle 6 is lowered from the top dead center to pierce through the base cloth and to be inserted into a needle insertion hole Ta of the looper T that is stopped, and a thread S is wound around the needle shank of the bearded needle 6 by the clockwise rotation of the looper T during lowering of the bearded needle 6. As illustrated in steps (6) to (10), the thread S is hooked by a hooking portion 7 by elevating the bearded needle 6 during rotating of the looper T clockwise, and a new loop P is formed on the base cloth C by elevating the bearded needle 6 to the top dead center to pierce through the base cloth C. In this step, rotation of the looper T is stopped, and the looper T is then rotated counterclockwise to an initial position, and the loop P1 is off-hooked from the hooking portion 7 by moving the base cloth C in the direction Y indicated by an arrow, resulting in loop stitches being formed by repeating the same steps.
In loop stitch, as is obvious from FIG. 7, if a thread is not off-hooked from a hooking portion of a bearded needle at a constant timing, irregularity in the size and standing angle of loops is caused, and hence clear embroidery patterns cannot be attained. Therefore, in order to realize clearly finished embroideries, off-hooking of the thread from the hooking portion of the bearded needle needs to be done regularly at a constant timing. The off-hooking of a thread from the hooking portion is done, as illustrated in FIG. 5A, at a step where a bearded needle 6 is being lowered after the bearded needle 6 has once reached a top dead center after a thread S is drawn out by a hooking portion 7. As illustrated in FIG. 5B, however, in the conventional art, the tension of the thread S could loosen when the bearded needle 6 is slightly lowered from the top dead center, and thereby the tip portion of the bearded needle 6 could be inserted and pierced between the twists (parts of the thread Sa, Sb) of the stranded thread S. Especially, in loop stitch with a narrow stitching interval, the possibility of the thread S being trapped by the tip portion of the bearded needle 6 is high, and if such a trapping occurs, and the thread is not broken, a poor-finished embroidery in which the stitches of chain stitch are formed on a base cloth is provided.